RE: [PATCH] ACPICA / hwreg: Use acpi_gbl_reduced_hardware to prevent accessing PM registers

-----Original Message----- From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Hanjun Guo Sent: Wednesday, September 18, 2013 5:28 PM To: Moore, Robert Cc: 'Rafael J. Wysocki'; 'Len Brown'; Box, David E; Zheng, Lv; 'linux-acpi@vger.kernel.org'; 'patches@linaro.org'; 'linaro-kernel@lists.linaro.org'; 'linaro-acpi@lists.linaro.org' Subject: Re: [PATCH] ACPICA / hwreg: Use acpi_gbl_reduced_hardware to prevent accessing PM registers

On 2013-9-17 1:26, Moore, Robert wrote:

...

• #define ACPI_REDUCED_HARDWARE TRUE

The intent of this feature is of course, to remove all code that is not needed -- specifically for hardware-reduced machines where the size

of the kernel is important.

Ok, how about this patch below, is it reasonable to you?

From b10bc1d2f9a3ff09abfb6990412aa1cf62d56937 Mon Sep 17 00:00:00 2001 From: Hanjun Guo hanjun.guo@linaro.org Date: Wed, 18 Sep 2013 17:19:23 +0800 Subject: [PATCH] ACPI: Introduce CONFIG_ACPI_REDUCED_HARDWARE to enable reduced hardware

If we want to enable reduced hardware ACPI on some platform (such as ARM), we need to modify the kernel code and set ACPI_REDUCED_HARDWARE to TRUE.

This is not reasonable, so introduce a kernel config to enable it, and no need for kernel modification when we use hardware-reduced ACPI.

Signed-off-by: Hanjun Guo hanjun.guo@linaro.org

drivers/acpi/Kconfig | 8 ++++++++ include/acpi/acconfig.h | 4 ++++ 2 files changed, 12 insertions(+)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 0d7f6eb..1232a7b 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -413,6 +413,14 @@ config ACPI_BGRT data from the firmware boot splash. It will appear under /sys/firmware/acpi/bgrt/ .

+config ACPI_REDUCED_HARDWARE

•   bool "Hardware-reduced ACPI support"
  

•   depends on ARM || ARM64
  

•    help
  

•     This config adds support for Hardware-reduced ACPI. When this option
  

•     is selected, will generate a specialized version of ACPICA that ONLY
  

•     supports the ACPI 5.0 "reduced hardware".
  

source "drivers/acpi/apei/Kconfig"

endif # ACPI diff --git a/include/acpi/acconfig.h b/include/acpi/acconfig.h index 1c16f82..15254f5 100644 --- a/include/acpi/acconfig.h +++ b/include/acpi/acconfig.h @@ -100,7 +100,11 @@

•  ACPI PM timer
  

•  FACS table (Waking vectors and Global Lock)
  

*/ +#ifdef CONFIG_ACPI_REDUCED_HARDWARE +#define ACPI_REDUCED_HARDWARE TRUE +#else #define ACPI_REDUCED_HARDWARE FALSE +#endif /* CONFIG_ACPI_REDUCED_HARDWARE */

The acconfig.h is not meant to be modified by OSPM and CONFIG_ACPI_REDUCED_HARDWARE does not belong to ACPICA, so it should go into include/acpi/platform/aclinux.h. Well, I believe no one has ever tested the codes marked out by the ACPI_REDUCED_HARDWARE configurable.

Thanks -Lv

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1.7.9.5

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